Netflix Effect on Guest Wi-FiWhat is the real impact of devices using using Netflix on a Wi-Fi network

Jim Palmer• Couple of wireless certs • Some FCC licenses • I’m on Twitter @WirelessJimP • I write a blog • Still no network certs • I “work” at “An Airport”

Rate Limiting Guests• Many times the conversation comes up around rate limiting.

• Yes, I have dual 10 Gbps Internet Connections.

• No, the rate limiting I’m talking about is on the wire, not on the air.

• DON’T turn off the higher data rates, that’s just bad!

• If you only have a 10 Mbps WAN connection due to ISP limitations, maybe consider blocking all streaming services, much like airlines do for inflight Wi-Fi.

Testing Setup

Netflix: Download vs Stream

• Customer intent will determine if they will download or if they will stream.

• Originally, my intent was to only look at downloading movies, which is one of my predominate traffic flows.

• During this testing, streaming revealed a much more intriguing use case.

• No one goes to the doctors office to download a movie and you can’t stream video inflight.

Netflix DownloadsNo Rate Limit down to 2.5 MbpsNone 25 Mbps

2.5 Mbps10 Mbps

Netflix Downloads

No Rate Limit

2.5 Mbps Rate Limit

What a Bottle Neck Looks Like

Netflix Downloads

Gratuitous Line Graph

Netflix StreamingNo Rate Limit down to 2.5 MbpsNone 25 Mbps

2.5 Mbps10 Mbps

Netflix Streaming

No Rate Limit

Netflix Streaming

25 Mbps Rate Limit

Netflix Streaming

10 Mbps Rate Limit

Netflix Streaming

2.5 Mbps Rate Limit

Netflix Streaming

2.5 Mbps Rate Limit Continued

Netflix Streaming2.5 Mbps Rate Limit

2 CLIENTS

YouTube StreamingNo Rate Limit down to 2.5 MbpsNone 25 Mbps

10 Mbps 2.5 Mbps

Lessons I’ve LearnedFrom Peter Mackenzie: From Joel Crane:

Start

Select Backoff

CCA?

NAV=0?

Wait DIFS

Backoff = 0?

Decrement BackoffCCA?

NAV=0? Transmit

Yes

No

No

No

Yes

No

Yes

Yes

Yes

No

DCF SummaryAKA

What it takes to send ONE frame in Wi-Fi

Lessons I’ve LearnedFrom Sam Clements:

It DependsTM

Thank You